I have completed both Composition I and II college level courses with a final grade: "A".

or

I have completed both Composition I and II college level courses with a final grade, "A".

or...

I have completed both Composition I and II college level courses with a final grade of "A".

or...


Something else entirely?

the third one

I would say "I have completed both Composition I and II college level courses with a final grade of "A"

As an English major and the child of two English professors I can tell you that all three sentences are a little muddled. The best way would be to say, "

I have completed college level Composition I and II courses with a final grade of "A"."

Or, "I have received the final grade of 'A' in both Composition I and II."

I'm not sure what this is for, but in most cases, the term "college level" is not going to be necessary.